Special Conditions: Bombardier Aerospace Inc., Models BD-500-1A10 and BD-500-1A11 Series Airplanes; Autobraking System Loads, 67321-67323 [2013-26936]

Download as PDF Federal Register / Vol. 78, No. 218 / Tuesday, November 12, 2013 / Proposed Rules The FAA issues special conditions, as defined in 14 CFR 11.19, under § 11.38, and they become part of the typecertification basis under § 21.17(a)(2). Novel or Unusual Design Features The Airbus Model A350–900 series will incorporate the following novel or unusual design features: an Electronic Flight Control system (EFCS), that when operating in its normal mode, will prevent airplane pitch attitudes greater than +30 degrees and less than –15 degrees, and roll angles greater than plus or minus 67 degrees. In addition, positive spiral stability is introduced for roll angles greater than 33 degrees at speeds below VMO/MMO. At speeds greater than VMO and up to VDF, maximum aileron control force is limited to only 45 degrees maximum bank angle. Discussion It is expected that high thrust-toweight ratios will provide the most critical cases for the positive pitch limit. A margin in pitch control must be available to enable speed control in maneuvers such as climb after takeoff, and balked landing climb. The pitch limit must not impede likely maneuvering made necessary by collision avoidance efforts. A negative pitch limit must similarly not interfere with collision avoidance capability or with attaining and maintaining speeds near VMO/MMO for emergency descent. Spiral stability, which is introduced above 33 degrees roll angle, and the roll limit must not restrict attaining roll angles up to 66 degrees (approximately 2.5g level turn) with flaps up and 60 degrees (approximately 2.0g level turn) with flaps down. The implementation of this spiral stability will require a steady aileron control force to maintain a constant bank angle above 33 degrees. This force must not require excessive pilot strength as stated in § 25.143(f). List of Subjects in 14 CFR Part 25 Aircraft, Aviation safety, Reporting and recordkeeping requirements. The authority citation for these special conditions is as follows: Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704. The Proposed Special Conditions Accordingly, the Federal Aviation Administration (FAA) proposes the following special conditions as part of the type certification basis for Airbus Model A350–900 series airplanes. In addition to § 25.143, the following requirements apply: 1. The pitch limiting function must not impede normal maneuvering for pitch angles up to the maximum required for normal maneuvering, including a normal all-engines operating takeoff, plus a suitable margin to allow for satisfactory speed control. 2. The pitch and roll limiting functions must not restrict or prevent attaining pitch attitudes necessary for emergency maneuvering or roll angles up to 66 degrees with flaps up, or 60 degrees with flaps down. Spiral stability, which is introduced above 33 degrees roll angle, must not require excessive pilot strength to achieve these limit roll angles. Other protections, which further limit the roll capability under certain extreme angle of attack or attitude or high speed conditions, are acceptable, as long as they allow at least 45 degrees of roll capability. Issued in Renton, Washington, on October 22, 2013. Stephen P. Boyd, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 2013–26928 Filed 11–8–13; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration mstockstill on DSK4VPTVN1PROD with PROPOSALS Applicability 14 CFR Part 25 As discussed above, these proposed special conditions apply to Airbus Model A350–900 series airplanes. Should Airbus apply later for a change to the type certificate to include another model incorporating the same novel or unusual design feature, the proposed special conditions would apply to that model as well. [Docket No.FAA–2013–0942; Notice No. 25– 13–30–SC] Conclusion This action affects only certain novel or unusual design features on the Airbus Model A350–900 series airplanes. It is not a rule of general applicability. VerDate Mar<15>2010 17:21 Nov 08, 2013 Jkt 232001 Special Conditions: Bombardier Aerospace Inc., Models BD–500–1A10 and BD–500–1A11 Series Airplanes; Autobraking System Loads Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed special conditions. AGENCY: This action proposes special conditions for the Bombardier Aerospace Inc. Models BD–500–1A10 SUMMARY: PO 00000 Frm 00003 Fmt 4702 Sfmt 4702 67321 and BD–500–1A11 series airplanes. These airplanes will have novel or unusual design features associated with the autobraking system for use during landing. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These proposed special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. DATES: Send your comments on or before December 27, 2013. ADDRESSES: Send comments identified by docket number FAA–2013–0942 using any of the following methods: • Federal eRegulations Portal: Go to https://www.regulations.gov/and follow the online instructions for sending your comments electronically. • Mail: Send comments to Docket Operations, M–30, U.S. Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room W12–140, West Building Ground Floor, Washington, DC, 20590–0001. • Hand Delivery or Courier: Take comments to Docket Operations in Room W12–140 of the West Building Ground Floor at 1200 New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except federal holidays. • Fax: Fax comments to Docket Operations at 202–493–2251. Privacy: The FAA will post all comments it receives, without change, to https://www.regulations.gov/, including any personal information the commenter provides. Using the search function of the docket Web site, anyone can find and read the electronic form of all comments received into any FAA docket, including the name of the individual sending the comment (or signing the comment for an association, business, labor union, etc.). DOT’s complete Privacy Act Statement can be found in the Federal Register published on April 11, 2000 (65 FR 19477– 19478), as well as at https:// DocketsInfo.dot.gov/. Docket: Background documents or comments received may be read at https://www.regulations.gov/ at any time. Follow the online instructions for accessing the docket or go to the Docket Operations in Room W12–140 of the West Building Ground Floor at 1200 New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except federal holidays. FOR FURTHER INFORMATION CONTACT: Mark Freisthler, FAA, Airframe and Cabin Safety Branch, ANM–115 Transport Airplane Directorate, Aircraft E:\FR\FM\12NOP1.SGM 12NOP1 67322 Federal Register / Vol. 78, No. 218 / Tuesday, November 12, 2013 / Proposed Rules Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057–3356; telephone 425–227–1119; facsimile 425–227–1232. SUPPLEMENTARY INFORMATION: Comments Invited We invite interested people to take part in this rulemaking by sending written comments, data, or views. The most helpful comments reference a specific portion of the special conditions, explain the reason for any recommended change, and include supporting data. We will consider all comments we receive on or before the closing date for comments. We may change these special conditions based on the comments we receive. mstockstill on DSK4VPTVN1PROD with PROPOSALS Background On December 10, 2009, Bombardier Inc. applied for a type certificate for their new Models BD–500–1A10 and BD–500–1A11 series airplanes (hereafter collectively referred to as ‘‘C-series’’). The C-series airplanes are swept-wing monoplanes with a pressurized cabin. They share an identical supplier base and significant common design elements. The fuselage is an aluminum alloy material, blended double-bubble design, sized for nominal 5-abreast seating. Each airplane’s powerplant consists of two under wing Pratt and Whitney PW1524G ultra-high bypass, geared turbofan engines. Flight controls are fly-by-wire systems with two passive/uncoupled side sticks. Avionics include five landscape primary cockpit displays. The dimensions of the airplanes encompass a wingspan of 115 feet; a height of 37.75 feet; and a length of 114.75 feet for the Model BD–500– 1A10 and 127 feet for the Model BD– 500–1A11. Passenger capacity is designated as 110 for the Model BD– 500–1A10 and 125 for the Model BD– 500–1A11. Maximum takeoff weight is 131,000 pounds for the Model BD–500– 1A10 and 144,000 pounds for the Model BD–500–1A11. Maximum takeoff thrust is 21,000 pounds for the Model BD– 500–1A10 and 23,300 pounds for the Model BD–500–1A11. Range is 3,394 miles (5,463 kilometres) for both models of airplanes. Maximum operating altitude is 41,000 feet for both models of airplanes. Type Certification Basis Under the provisions of Title 14, Code of Federal Regulations (14 CFR) 21.17, Bombardier Inc. must show that the Cseries airplanes meet the applicable provisions of part 25 as amended by Amendments 25–1 through 25–129. VerDate Mar<15>2010 17:21 Nov 08, 2013 Jkt 232001 If the Administrator finds that the applicable airworthiness regulations (i.e., 14 CFR part 25) do not contain adequate or appropriate safety standards for the C-series airplanes because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16. Special conditions are initially applicable to the model for which they are issued. Should the type certificate for that model be amended later to include any other model that incorporates the same or similar novel or unusual design feature, the special conditions would also apply to the other model under § 21.101. In addition to the applicable airworthiness regulations and special conditions, the C-series airplanes must comply with the fuel vent and exhaust emission requirements of 14 CFR part 34 and the noise certification requirements of 14 CFR part 36, and the FAA must issue a finding of regulatory adequacy under § 611 of Public Law 92– 574, the ‘‘Noise Control Act of 1972.’’ The FAA issues special conditions, as defined in 14 CFR 11.19, in accordance with § 11.38, and they become part of the type certification basis under § 21.17(a)(2). potentially higher gear and airframe loads. Part 25 does not contain adequate requirements to address the potentially higher structural loads that could result from this type of braking system. In addition, the effects on fatigue covered by § 25.571 also need to be considered. Therefore, FAA has determined that additional airworthiness standards are needed for the certification of this unusual design feature. These special conditions propose airworthiness standards for the certification of the Cseries airplanes with an autobrake system. Novel or Unusual Design Features List of Subjects in 14 CFR Part 25 Aircraft, Aviation safety, Reporting and recordkeeping requirements. The authority citation for these special conditions is as follows: The C-series airplanes will incorporate the following novel or unusual design features: The C-series airplanes possess an autobrake system. This is a pilot-selectable function that allows earlier maximum braking at landing without pilot pedal input. When the autobrake system is armed before landing, it automatically commands maximum braking at main wheels touchdown. Normal procedures remain unchanged and call for manual braking after nose wheel touchdown. Applicability As discussed above, these special conditions are applicable to the Models BD–500–1A10 and BD–500–1A11 series airplanes. Should Bombardier Inc. apply at a later date for a change to the type certificate to include another model incorporating the same novel or unusual design feature, the special conditions would apply to that model as well. Conclusion This action affects only certain novel or unusual design features on one series of airplanes. It is not a rule of general applicability. Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704. Discussion The Proposed Special Conditions Accordingly, the Federal Aviation Administration (FAA) proposes the following special conditions as part of the type certification basis for Bombardier Inc. Models BD–500–1A10 and BD–500–1A11 series airplanes. Section 25.493 addresses braked roll loads but does not contain a specific ‘‘pitchover’’ requirement addressing the loading on the nose gear, the nose gear surrounding structure, and the forward fuselage. Moreover, § 25.493 specifies airplane attitudes in accordance with figure 6 of appendix A to part 25, which are level landing attitudes. For airplanes with traditional braking systems, the current ground load requirements are considered adequate for the design of the nose gear and airframe structure. However, the C-Series airplane autobrake system, which could apply maximum braking at the main wheels with the airplane in a tail-down attitude well before the nose touches down, will cause a high nose gear sink rate and Autobraking System Loads A landing pitchover condition must be addressed that takes into account the effect of the autobrake system. The airplane is assumed to be at the design maximum landing weight, or at the maximum weight allowed with the autobrake system on. The airplane is assumed to land in a tail-down attitude at the speeds defined by § 25.481. Following main gear contact, the airplane is assumed to rotate about the main gear wheels at the highest pitch rate generated by the autobrake system. This is considered a limit load condition from which ultimate loads must also be determined. Loads must be determined for a critical fuel and payload distribution and centers of PO 00000 Frm 00004 Fmt 4702 Sfmt 4702 E:\FR\FM\12NOP1.SGM 12NOP1 Federal Register / Vol. 78, No. 218 / Tuesday, November 12, 2013 / Proposed Rules gravity. Nose gear loads, as well as airframe loads, must be determined. The airplane must support these loads as described in § 25.305. In addition to the above airworthiness standards, fatigue loads must also be determined and applied in accordance to § 25.571. Issued in Renton, Washington, on November 1, 2013. Jeffrey E. Duven, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 2013–26936 Filed 11–8–13; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 25 [Docket No. FAA–2013–0897; Notice No. 25– 13–29–SC] Special Conditions: Airbus, Model A350–900 Series Airplane; Transient Engine Failure Loads Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed special conditions. AGENCY: This action proposes special conditions for Airbus Model A350–900 series airplanes. These airplanes will have a novel or unusual design feature associated with the new generation of high bypass engines and the potential loads resulting from extreme engine failure conditions. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These proposed special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. DATES: Send your comments on or before December 27, 2013. ADDRESSES: Send comments identified by docket number FAA–2013–0897 using any of the following methods: • Federal eRegulations Portal: Go to https://www.regulations.gov/ and follow the online instructions for sending your comments electronically. • Mail: Send comments to Docket Operations, M–30, U.S. Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room W12–140, West Building Ground Floor, Washington, DC 20590–0001. • Hand Delivery or Courier: Take comments to Docket Operations in mstockstill on DSK4VPTVN1PROD with PROPOSALS SUMMARY: VerDate Mar<15>2010 17:21 Nov 08, 2013 Jkt 232001 Room W12–140 of the West Building Ground Floor at 1200 New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except federal holidays. • Fax: Fax comments to Docket Operations at 202–493–2251. Privacy: The FAA will post all comments it receives, without change, to https://www.regulations.gov/, including any personal information the commenter provides. Using the search function of the docket Web site, anyone can find and read the electronic form of all comments received into any FAA docket, including the name of the individual sending the comment (or signing the comment for an association, business, labor union, etc.). DOT’s complete Privacy Act Statement can be found in the Federal Register published on April 11, 2000 (65 FR 19477– 19478), as well as at https:// DocketsInfo.dot.gov/. Docket: Background documents or comments received may be read at https://www.regulations.gov/ at any time. Follow the online instructions for accessing the docket or go to the Docket Operations in Room W12–140 of the West Building Ground Floor at 1200 New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except federal holidays. FOR FURTHER INFORMATION CONTACT: Todd Martin, FAA, International Branch, ANM–115, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington 98057–3356; telephone (425) 227–1178; facsimile (425) 227–1320. SUPPLEMENTARY INFORMATION: Comments Invited We invite interested people to take part in this rulemaking by sending written comments, data, or views. The most helpful comments reference a specific portion of the proposed special conditions, explain the reason for any recommended change, and include supporting data. We will consider all comments we receive on or before the closing date for comments. We may change these special conditions based on the comments we receive. Background On August 25, 2008, Airbus applied for a type certificate for their new Model A350–900 series airplane. Later, Airbus requested and the FAA approved an extension to the application for FAA type certification to June 28, 2009. The Model A350–900 series has a conventional layout with twin wing- PO 00000 Frm 00005 Fmt 4702 Sfmt 4702 67323 mounted Rolls-Royce Trent engines. It features a twin aisle 9-abreast economy class layout, and accommodates side-byside placement of LD–3 containers in the cargo compartment. The basic Model A350–900 series configuration will accommodate 315 passengers in a standard two-class arrangement. The design cruise speed is Mach 0.85 with a Maximum Take-Off Weight of 602,000 lbs. Airbus proposes the Model A350– 900 series to be certified for extended operations (ETOPS) beyond 180 minutes at entry into service for up to a 420minute maximum diversion time. The existing regulations are inadequate because the new, large bypass fan engines of the Model A350– 900 series airplanes can cause more damage in a failure event than the previous engines. To maintain the level of safety envisioned by Title 14, Code of Federal Regulations (14 CFR) 25.61(b), more comprehensive criteria are needed for the new generation of high bypass engines. The more severe events resulting from extreme engine failure conditions would be treated as dynamic load conditions. The proposed special conditions would distinguish between the more common engine failure events and those rare events resulting from structural failures. The more common events would continue to be treated as static torque limit load conditions. The severe events would be considered ultimate loads, and include all transient loads associated with the event. An additional safety factor would be applied to the more critical airframe supporting structure. Type Certification Basis Under Title 14, Code of Federal Regulations (14 CFR) 21.17, Airbus must show that the Model A350–900 series meets the applicable provisions of 14 CFR part 25, as amended by Amendments 25–1 through 25–128. If the Administrator finds that the applicable airworthiness regulations (i.e., 14 CFR part 25) do not contain adequate or appropriate safety standards for the Model A350–900 series airplane because of a novel or unusual design feature, special conditions are prescribed under § 21.16. Special conditions are initially applicable to the model for which they are issued. Should the type certificate for that model be amended later to include any other model that incorporates the same or similar novel or unusual design feature, the proposed special conditions would also apply to the other model under § 21.101. In addition to the applicable airworthiness regulations and proposed special conditions, the Model A350–900 E:\FR\FM\12NOP1.SGM 12NOP1

Agencies

[Federal Register Volume 78, Number 218 (Tuesday, November 12, 2013)]
[Proposed Rules]
[Pages 67321-67323]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-26936]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No.FAA-2013-0942; Notice No. 25-13-30-SC]

Special Conditions: Bombardier Aerospace Inc., Models BD-500-1A10
and BD-500-1A11 Series Airplanes; Autobraking System Loads

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

-----------------------------------------------------------------------

SUMMARY: This action proposes special conditions for the Bombardier
Aerospace Inc. Models BD-500-1A10 and BD-500-1A11 series airplanes.
These airplanes will have novel or unusual design features associated
with the autobraking system for use during landing. The applicable
airworthiness regulations do not contain adequate or appropriate safety
standards for this design feature. These proposed special conditions
contain the additional safety standards that the Administrator
considers necessary to establish a level of safety equivalent to that
established by the existing airworthiness standards.

DATES: Send your comments on or before December 27, 2013.

ADDRESSES: Send comments identified by docket number FAA-2013-0942
using any of the following methods:
Federal eRegulations Portal: Go to https://www.regulations.gov/and follow the online instructions for sending your
comments electronically.
Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room
W12-140, West Building Ground Floor, Washington, DC, 20590-0001.
Hand Delivery or Courier: Take comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m.,
Monday through Friday, except federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
Privacy: The FAA will post all comments it receives, without
change, to https://www.regulations.gov/, including any personal
information the commenter provides. Using the search function of the
docket Web site, anyone can find and read the electronic form of all
comments received into any FAA docket, including the name of the
individual sending the comment (or signing the comment for an
association, business, labor union, etc.). DOT's complete Privacy Act
Statement can be found in the Federal Register published on April 11,
2000 (65 FR 19477- 19478), as well as at https://DocketsInfo.dot.gov/.
Docket: Background documents or comments received may be read at
https://www.regulations.gov/ at any time. Follow the online instructions
for accessing the docket or go to the Docket Operations in Room W12-140
of the West Building Ground Floor at 1200 New Jersey Avenue SE.,
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday,
except federal holidays.

FOR FURTHER INFORMATION CONTACT: Mark Freisthler, FAA, Airframe and
Cabin Safety Branch, ANM-115 Transport Airplane Directorate, Aircraft

[[Page 67322]]

Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057-
3356; telephone 425-227-1119; facsimile 425-227-1232.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite interested people to take part in this rulemaking by
sending written comments, data, or views. The most helpful comments
reference a specific portion of the special conditions, explain the
reason for any recommended change, and include supporting data.
We will consider all comments we receive on or before the closing
date for comments. We may change these special conditions based on the
comments we receive.

Background

On December 10, 2009, Bombardier Inc. applied for a type
certificate for their new Models BD-500-1A10 and BD-500-1A11 series
airplanes (hereafter collectively referred to as ``C-series''). The C-
series airplanes are swept-wing monoplanes with a pressurized cabin.
They share an identical supplier base and significant common design
elements. The fuselage is an aluminum alloy material, blended double-
bubble design, sized for nominal 5-abreast seating. Each airplane's
powerplant consists of two under wing Pratt and Whitney PW1524G ultra-
high bypass, geared turbofan engines. Flight controls are fly-by-wire
systems with two passive/uncoupled side sticks. Avionics include five
landscape primary cockpit displays. The dimensions of the airplanes
encompass a wingspan of 115 feet; a height of 37.75 feet; and a length
of 114.75 feet for the Model BD-500-1A10 and 127 feet for the Model BD-
500-1A11. Passenger capacity is designated as 110 for the Model BD-500-
1A10 and 125 for the Model BD-500-1A11. Maximum takeoff weight is
131,000 pounds for the Model BD-500-1A10 and 144,000 pounds for the
Model BD-500-1A11. Maximum takeoff thrust is 21,000 pounds for the
Model BD-500-1A10 and 23,300 pounds for the Model BD-500-1A11. Range is
3,394 miles (5,463 kilometres) for both models of airplanes. Maximum
operating altitude is 41,000 feet for both models of airplanes.

Type Certification Basis

Under the provisions of Title 14, Code of Federal Regulations (14
CFR) 21.17, Bombardier Inc. must show that the C-series airplanes meet
the applicable provisions of part 25 as amended by Amendments 25-1
through 25-129.
If the Administrator finds that the applicable airworthiness
regulations (i.e., 14 CFR part 25) do not contain adequate or
appropriate safety standards for the C-series airplanes because of a
novel or unusual design feature, special conditions are prescribed
under the provisions of Sec. 21.16.
Special conditions are initially applicable to the model for which
they are issued. Should the type certificate for that model be amended
later to include any other model that incorporates the same or similar
novel or unusual design feature, the special conditions would also
apply to the other model under Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the C-series airplanes must comply with the fuel vent and
exhaust emission requirements of 14 CFR part 34 and the noise
certification requirements of 14 CFR part 36, and the FAA must issue a
finding of regulatory adequacy under Sec. 611 of Public Law 92-574,
the ``Noise Control Act of 1972.''
The FAA issues special conditions, as defined in 14 CFR 11.19, in
accordance with Sec. 11.38, and they become part of the type
certification basis under Sec. 21.17(a)(2).

Novel or Unusual Design Features

The C-series airplanes will incorporate the following novel or
unusual design features: The C-series airplanes possess an autobrake
system. This is a pilot-selectable function that allows earlier maximum
braking at landing without pilot pedal input. When the autobrake system
is armed before landing, it automatically commands maximum braking at
main wheels touchdown. Normal procedures remain unchanged and call for
manual braking after nose wheel touchdown.

Discussion

Section 25.493 addresses braked roll loads but does not contain a
specific ``pitchover'' requirement addressing the loading on the nose
gear, the nose gear surrounding structure, and the forward fuselage.
Moreover, Sec. 25.493 specifies airplane attitudes in accordance with
figure 6 of appendix A to part 25, which are level landing attitudes.
For airplanes with traditional braking systems, the current ground load
requirements are considered adequate for the design of the nose gear
and airframe structure. However, the C-Series airplane autobrake
system, which could apply maximum braking at the main wheels with the
airplane in a tail-down attitude well before the nose touches down,
will cause a high nose gear sink rate and potentially higher gear and
airframe loads.
Part 25 does not contain adequate requirements to address the
potentially higher structural loads that could result from this type of
braking system. In addition, the effects on fatigue covered by Sec.
25.571 also need to be considered. Therefore, FAA has determined that
additional airworthiness standards are needed for the certification of
this unusual design feature. These special conditions propose
airworthiness standards for the certification of the C-series airplanes
with an autobrake system.

Applicability

As discussed above, these special conditions are applicable to the
Models BD-500-1A10 and BD-500-1A11 series airplanes. Should Bombardier
Inc. apply at a later date for a change to the type certificate to
include another model incorporating the same novel or unusual design
feature, the special conditions would apply to that model as well.

Conclusion

This action affects only certain novel or unusual design features
on one series of airplanes. It is not a rule of general applicability.

List of Subjects in 14 CFR Part 25

Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The authority citation for these special conditions is as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Proposed Special Conditions

Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Bombardier Inc. Models BD-500-1A10 and BD-500-1A11 series
airplanes.

Autobraking System Loads

A landing pitchover condition must be addressed that takes into
account the effect of the autobrake system. The airplane is assumed to
be at the design maximum landing weight, or at the maximum weight
allowed with the autobrake system on. The airplane is assumed to land
in a tail-down attitude at the speeds defined by Sec. 25.481.
Following main gear contact, the airplane is assumed to rotate about
the main gear wheels at the highest pitch rate generated by the
autobrake system. This is considered a limit load condition from which
ultimate loads must also be determined. Loads must be determined for a
critical fuel and payload distribution and centers of

[[Page 67323]]

gravity. Nose gear loads, as well as airframe loads, must be
determined. The airplane must support these loads as described in Sec.
25.305.
In addition to the above airworthiness standards, fatigue loads
must also be determined and applied in accordance to Sec. 25.571.

Issued in Renton, Washington, on November 1, 2013.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2013-26936 Filed 11-8-13; 8:45 am]
BILLING CODE 4910-13-P

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